The present invention relates to a cleaning device for use in a cleaning apparatus in which a cleaning fluid is supplied onto a substrate to be cleaned, e.g. a semiconductor wafer, which is being rotated in a horizontal position, and while doing so, the substrate is cleaned with the cleaning device. The present invention also relates to a substrate cleaning apparatus using the above-described cleaning device.
A conventional cleaning device of the type described above has a structure shown in FIG. 1. The cleaning device, as shown in FIG. 1, includes a disk-shaped sponge member 101, which is a cleaning member, and a cleaning member holding mechanism 102 for holding the sponge member 101. The cleaning member holding mechanism 102 includes a columnar holder body 103 having a frusto-conical portion at the lower end thereof and a collar portion at the upper end thereof. The cleaning member holding mechanism 102 further includes a ring member 104 fitted on the outer peripheral portion of the holder body 103. The lower end portion of the ring member 104 is drawn so as to form a predetermined gap between itself and the outer periphery of the frusto-conical portion of the holder body 103.
With the sponge member 101 placed in abutment on the frusto-conical portion of the holder body 103, the ring member 104 is fitted onto the outer peripheral portion of the holder body 103, thereby holding the sponge member 101 between the outer periphery of the holder body 103 and the inner periphery of the ring member 104. Thus, the sponge member 101 is fitted in the cleaning member holding mechanism 102. The holder body 103 is provided with a tapped hole 106 for threaded engagement with the distal end of a rotating shaft for holding and rotating the cleaning device. The holder body 103 and the ring member 104 are secured to each other with a screw 105. However, the cleaning device having the above-described structure suffers from some problems as stated below.
{circle around (1)} Because the sponge member 101 is held between the holder body 103 and the ring member 104, a jig is needed to correctly fit the sponge member 101 into the cleaning member holding mechanism 102, and some experience is required to carry out the fitting operation.
{circle around (2)} As shown in FIG. 5(a), the sponge member 101 and the cleaning member holding mechanism 102 are moved in approximately the diametrical direction of a substrate Wf to be cleaned with the sponge member 101 placed in contact with the rotating substrate Wf within a range in which there is no interference between a projection (chuck) 111 of a substrate holding and rotating mechanism for holding and rotating the substrate Wf and either of the cleaning member holding mechanism 102 and the sponge member 101. When the cleaning member holding mechanism 102 and the sponge member 101 are moved in this way, a contact surface of the sponge member 101 that comes in contact with the substrate Wf is unable to sufficiently cover the edge portion Wfa. Consequently, the range of cleaning does not extend to the edge portion Wfa. In other words, the radius R1 of the cleaning range of the cleaning device is small, and the edge portion E1 of the substrate Wf left uncleaned is undesirably large in area.
{circle around (3)} The corner of the substrate contacting surface of the sponge member 101 is rounded. Accordingly, the area (outer diameter) of contact of the sponge member 101 with the substrate Wf readily changes with variations in pressure with which the sponge member 101 is pressed against the substrate Wf. Thus, variations in pressure applied to the sponge member 101 cause the cleaning range to change undesirably.
FIG. 2 shows the structure of another conventional cleaning device of the type described above. As shown in FIG. 2, the cleaning device includes a stepped columnar sponge member 201 having an upper portion with a larger outer diameter than that of a lower portion thereof. The cleaning device further includes a cleaning member holding mechanism 202 for holding the sponge member 201. The cleaning member holding mechanism 202 includes a stepped columnar holder body 203 having an upper portion with a larger outer diameter than that of a lower portion thereof. The cleaning member holding mechanism 202 further includes a ring member 204 that is brought into threaded engagement with the outer periphery of the lower portion of the holder body 203. The ring member 204 has a projection 204a projecting inward from the distal end thereof.
With the sponge member 201 placed in abutment against the holder body 203, the ring member 204 is brought into threaded engagement with the outer periphery of the lower portion of the holder body 203. Consequently, the projection 204a of the ring member 204 abuts against the step portion of the sponge member 201, and thus the upper portion of the sponge member 201 is held between the projection 204a and the holder body 203. In this way, the sponge member 201 is fitted in the cleaning member holding mechanism 202. The holder body 203 is formed with a tapped hole 205 for threaded engagement with the distal end of a rotating shaft for holding and rotating the cleaning device. The cleaning device having the above-described structure involves some problems as stated below.
{circle around (1)} Because the ring member 204 is connected to the holder body 203 by threaded engagement, it takes a great deal of time and labor to loosen or tighten the ring member 204 when the sponge member 201 is to be detached or attached.
{circle around (2)} In use, a sponge swells with cleaning water or the like and slightly increases in volume. In this regard, the sponge member 201 is held by the holder body 203 and the ring member 204 in the cleaning device having the structure shown in FIG. 2. Therefore, expansion occurs markedly at the substrate contacting surface of the sponge member 201, and the sponge member 201 tends to swell convexly at the center of the substrate contacting surface (as shown by the chain double-dashed line in FIG. 2). This may cause damage to the surface of a film formed on the surface of the substrate to be cleaned, depending on the kind of film.
{circle around (3)} Unlike the cleaning member shown in FIG. 1, the sponge member 201 of the cleaning device shown in FIG. 2 is shaped such that the outer peripheral portion thereof forms right angles to the lower surface thereof (i.e. the corner is not rounded). Therefore, the area of contact of the sponge member 201 with the substrate to be cleaned seems to be wide. However, in the case of the cleaning device shown in FIG. 2, the amount L that the sponge member 201 projects from the lower end of the ring member 204 needs to be large in order to avoid interference between the cleaning member holding mechanism 202 and a chuck (not shown). Accordingly, when moved toward the outer periphery of the substrate, the sponge member 201 is deformed toward the center of the substrate as shown by the one-dot chain line in FIG. 2. In actuality, the outer diameter of contact of the sponge member 201 becomes small at the outer peripheral portion of the substrate. Therefore, the outer peripheral portion of the substrate is likely to be left uncleaned. Moreover, the deformation of the sponge member 201 causes variations (reduction) in the contact pressure of the sponge member 201 with respect to the substrate.
In view of the above-described circumstances, an object of the present invention is to provide a cleaning device designed so that a cleaning member, e.g. a sponge, which comes into contact with a substrate to be cleaned, is easy to fit to the cleaning device, and even when the cleaning member is deformed, the substrate can be cleaned right up to the edge, and further that the area of contact with the substrate is unlikely to change with variations in pressure with which the cleaning member is pressed against the substrate, and thus no damage is caused to the surface of a film formed on the substrate.
Another object of the present invention is to provide a substrate cleaning apparatus using the above-described cleaning device.
The present invention provides a cleaning device for use in a substrate cleaning apparatus. The cleaning device includes a cleaning member to be brought into contact with a surface of a substrate to be cleaned, and a cleaning member holding mechanism for holding the cleaning member. The cleaning member holding mechanism includes a holding member having a lower portion split into a plurality of chuck jaws or members, and a ring member fitted onto the outer periphery of the holding member. An end portion of the cleaning member is inserted into an insertion hole formed by the plurality of chuck jaws of the holding member, and the ring member is fitted onto the outer periphery of the holding member, thereby holding the cleaning member with the chuck jaws. Thus, the feature of the present invention resides in the cleaning member holding mechanism having a collet chuck structure.
By using a collet chuck structure to fit the cleaning member to the cleaning member holding mechanism, the cleaning member can be fitted to the cleaning member holding mechanism simply by inserting the end portion of the cleaning member into the insertion hole formed by the chuck jaws of the holding member and then fitting the ring member onto the outer periphery of the holding member.
Preferably, the corner of a portion of the cleaning member that comes in contact with the substrate is angled as viewed in a vertical section.
By virtue of the above-described arrangement, it becomes possible to include the edge portion of the substrate to be cleaned in the range of cleaning. In addition, because the corner of the contact portion is angled, but not rounded, the cleaning range does not change with variations in pressure applied to the cleaning member.
Preferably, the cleaning member has a stepped configuration as viewed in a vertical section in which a portion closer to the surface that comes in contact with the substrate to be cleaned is wider than a portion thereof that is inserted into the holding member, and the distal ends of the plurality of chuck jaws of the holding member are pressed against the step portion of the cleaning member.
By virtue of the above-described arrangement, even when the cleaning member is moved to the edge portion of the substrate being cleaned, a projection of a substrate holding and rotating mechanism that holds the substrate does not interfere with the outer periphery of the cleaning member holding mechanism, which holds the cleaning member. Accordingly, it becomes possible to include the edge portion of the substrate in the range of cleaning. In addition, because the distal ends of the chuck jaws are pressed against the step portion of the cleaning member, the cleaning member is held by the distal ends of the chuck jaws so that the substrate contacting surface of the cleaning member is prevented from being pushed up away from the substrate. Consequently, the pressure with which the contact surface of the cleaning member is pressed against the substrate becomes low in the center of the contact surface. Accordingly, the cleaning member does not cause damage to the surface of a film formed on the surface of the substrate.
Preferably, projections are provided on the surfaces of the chuck jaws of the holding member that come in contact with the cleaning member and/or a surface of the holding member contacted by the end surface of the portion of the cleaning member inserted into the insertion hole.
By virtue of the presence of the projections, the rotational force of the cleaning member holding mechanism can be satisfactorily transmitted to the cleaning member, so that even when the cleaning member is pressed against the substrate to be cleaned, the cleaning member holding mechanism can surely rotate the cleaning member without racing.
In addition, the present invention provides a cleaning device for cleaning a substrate by coming into contact with it. The cleaning device includes a cleaning member and a cleaning member holding mechanism for holding the cleaning member. The cleaning member has a stepped configuration in which the outer diameter of a portion closer to a surface of the cleaning member that comes into contact with the substrate is larger than the outer diameter of a portion of the cleaning member closer to the cleaning member holding mechanism, and a vertical section of the cleaning member taken along a line passing through the center thereof has an inverted T-shaped configuration.
By virtue of the above-described stepped configuration of the cleaning member, it becomes possible to include the edge portion of the substrate in the range of cleaning.
In any of the above-described cleaning devices, the cleaning member may be made of a porous material. Alternatively, the cleaning member may be a combination of a cloth holding member and a cloth bonded thereto.
In addition, the present invention provides a substrate cleaning apparatus including a substrate holding and rotating mechanism and a cleaning device, wherein a cleaning fluid is supplied onto a surface of a substrate to be cleaned that is being rotated in a horizontal position by the substrate holding and rotating mechanism, and the cleaning device is brought into contact with the surface of the substrate being rotated, thereby cleaning the surface of the substrate. One of the above-described cleaning devices is used as the cleaning device of the substrate cleaning apparatus.
The use of one of the above-described cleaning devices makes it possible to realize a substrate cleaning apparatus that exhibits the above-described advantageous effects of the cleaning device.
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings.